1. Field of the Invention
The present invention relates to an image recording apparatus, suitable for use in a digital copying machine, or the like, of the type in which an image of a document is read and stored, and in which the stored image information is recorded. The invention particularly relates to an image recording apparatus capable of judging, prior to execution of the recording operation instructed by an operator, as to whether there are or are not expendable supplies such as recording sheets, or the like, in the amount required for the chosen recording operation, and the invention further relates to an apparatus capable of preventing interruption of the recording operation because of a shortage of expendable supplies.
2. Discussion of the Related Art
Recently, with the spread of personal computers and word processors, etc., the types of image information to be copied, or likewise processed, has become diverse and large in quantity.
To cope with this phenomena, improvements in the quality of copied images has been necessary. Also, it has been necessary to increase flexibility and functions of copying machines over the traditional functions of number of copies and scale reduction/ enlargement.
Examples of the various functions which have been required in copying machines include electronic recirculating document handling (hereinafter abbreviated to "electronic RDH") in which a plurality of documents are copied a desired number of times for each document; and bookbinding in which images of a plurality of documents are suitably edited and copied in a manner so that images of two documents are copied on opposite ends of a sheet of recording paper so as to make a two page sheet, the sheets of recording paper on which images have been copied are stacked, and the stack is bound at the center and doubled into booklet in which the copies of the documents are arranged in the order of pages.
Other examples of functions which have been required in copying machines include image communication as in facsimile equipment, and printing for outputting information from a host computer, a personal computer, or the like.
Conventionally, copying machines in which the above-mentioned functions are available have been the so-called digital copying machines. In such a digital copying machine, documents are set in an automatic document feeder (hereinafter abbreviated to "ADF"), and the documents are automatically successively fed by the ADF onto a platen of the copying machine so that the image on each document is read by a scanner and stored in a storage device after it is converted into an electric signal.
Depending on the copying function designated by an operator, the image information of a document stored in the storage device is read out from the devise and converted into optical image information by a raster output scanner (hereinafter abbreviated to "ROS") unit so that image recording can be carried out through known electrophotographic copying processes.
During the electrophotographic copying process, at the time of image recording, expendable supplies such as recording sheets, toner, etc., stored in the copying machine are consumed. Accordingly, it is desirable to provide a digital copying machine with a function to detect and indicate existence of the expendable supplies.
If the copying machine is used as facsimile equipment, image information transmitted through a telephone line is stored in the storage device, and then the stored information is read out from the storage device and converted into an optical image by means of the ROS, or the like, so that image recording can be carried out through known electrophotographic copying processes.
On the other hand, when the above digital copying machine is used as a printer, image information transmitted from a host computer, or the like, is stored in the storage device, and then the information is read out from the storage device and converted into an optical image by the ROS, or the like, so that image recording can be carried by known electrophotographic copying processes.
In the copying machine discussed above there is the following problem. The prior-art digital copying machines have no function to detect and indicate the amount of expendable supplies such as recording sheets, toner, and the like, although they do have a function to detect and indicate the existence of expendable supplies such as recording sheets, toner, and the like.
Further, digital copying machines have, in addition to an ordinary document copying functions, various complicated functions such as an electronic RDH function in which a desired number of copies is made of plurality of documents and so on. Accordingly, it is it is difficult for an operator to estimate the amount of expendable supplies such as recording sheets, and the like, required for execution of a designated job based upon the number of sheets of documents and whether a function such as RDH or the like is to be executed. Sometimes, the expendable supplies, such as recording sheets, or the like, become used up during the copying operation. If the supplies are used up, the copying machine interrupts the copying operation and indicates the used-up state of the expendable supplies such as paper or toner, and thereby calls upon the operator to supplement the supplies. After the operator supplements the expendable supplies and pushes the start button again, the digital copying machine restarts the interrupted copying operation.
However, digital copying machines have complicated functions such as RDH, bookbinding, in addition to an ordinary document copying function. Accordingly, if sheets of recording paper, for example, become used up during the RDH function, the remainder portion of the job is restarted after additional recording paper is added. Therefore, the operator must examine the remaining number of pages of the documents for which the copying operation has been interrupted, and the remaining number of sheets of recording paper on which the copies are to be made so as to designate, on a control board, the number of pages of the documents, the number of sheets of recording paper, etc., on which the copying operation is restarted. Thus, the operation to start copying operation again after interruption of the copying operation is troublesome.
If the digital copying machine has the capability to act as facsimile equipment or a printer, there is sometimes a not-yet finished portion of a job stored in the storage device within the copying machine when an operator newly designates another job to be executed. In such a case, even if there is a sufficient quantity of expendable supplies such as sheets of recording paper, or the like, in the copying machine for execution of the job newly designated by the operator, the expendable supplies consumed by the not-yet finished job (for example, image recording for an incoming facsimile) so that the remaining quantity of the expendable supplies becomes inadequate to execute the job newly designated by the operator.
In this case, even if the quantity of expendable supplies such as sheets of recording paper, or the like, within the copying machine is examined, it is impossible to judge whether the newly designated job can be executed by the examined quantity of expendable supplies. Accordingly, in some cases, expendable supplies such as sheets of recording paper, or the like, may be used up in the copying operation so that the copying operation is interrupted. Also in this case, as described above, when copying operation is restarted after interruption of the copying operation, the operator is required to perform a complicated operation to examine the remaining number of pages of the documents, the remaining number of sheets of recording paper, etc., for which copying operation has been interrupted and to designate through control board the number of pages of the documents, the number of sheets of recording paper, etc., on which the copying operation be restarted. Thus, also in this case, the operation to start copying operation again after interruption is troublesome.